1. Field of the Invention
The present invention relates to a broadhead for an arrow having expanding cutting blades and, more particularly, to a broadhead having cutting blades which are held in an undeployed retracted position and moved to a deployed expanded position when the broadhead strikes a target.
2. Description of the Prior Art
Broadheads having cutting blades which are held in an undeployed retracted position and moved to a deployed expanded position when the arrow strikes a target are well known in the art. Broadheads designed with deployable cutting blades overcome the problems associated with wind drag and other adverse wind effects during the flight of the arrow. For example, U.S. Pat. No. 5,112,063 to Puckett discloses a broadhead having deployable cutting blades which are kept in a retracted position during the flight of an arrow by a tubular external restraint which fits over the ferrule of the broadhead. When the broadhead impacts against a target, such as an animal, a deployment mechanism causes the blades to be deployed, cutting the tubular restraint from the ferrule.
Various means for securing the expanding cutting blades to the ferrule of the broadhead have been developed in an effort to provide an aerodynamically balanced arrow with the capability of instantaneously deploying the cutting blades upon the arrow striking the target. Pivotable connecting pins are typically utilized for securing expanding cutting blades to the broadhead as disclosed in, for instance, U.S. Pat. No. 3,600,835 to Hendricks, U.S. Pat. No. 4,099,720 to Zeren, and U.S. Pat. No. 5,090,709 to Johnson, among others. Many other prior art broadheads provide pivotably connecting pins linking the expanding cutting blades to a plunger mechanism which causes the blades to deploy once the arrow strikes the target. These are disclosed in, for instance, U.S. Pat. No. 5,102,147 to Szeluga, and U.S. Pat. No. 5,112,063 to Puckett, among others.
The broadhead is typically secured to an arrow shaft via a threaded end portion of the broadhead. The threaded end portion may be threaded directly into the end of the arrow shaft. However, it is more common for the threaded end portion to be threaded into an insert which is secured within the end of the arrow shaft. A round flat washer is typically placed over the threaded end portion of the broadhead prior to joining the broadhead with the arrow shaft. In either case, either the washer or the end of the arrow shaft forms a shoulder which restrains the blades of the broadhead from deploying past a fixed point (i.e., the edge of the shoulder).
The shoulders formed by the structure associated with prior art broadheads and arrow shafts cause several disadvantages which may affect the performance of the arrow during use. For example, the edge of the shoulder puts stress on a single point of the blades which increases the possibility that a blade will crack upon impact with a hard surface, such as a bone of an animal. Also, the shoulder prevents blades from deploying in a further retracted position which may limit the penetration of the broadhead into the intended target.
The novel configuration of the washer used in connection with the broadhead of the present invention obviates the disadvantages encountered in the prior art by providing a means for distributing the stress exerted by the washer over a larger surface area of the blades while allowing the blades to deploy in a further retracted position.